BOSTON — Brian Cashman, the Yankees’ general manager, sat in the visitors’ dugout at Fenway Park yesterday and sounded like a satisfied and an optimistic man. And that was before his team went out and thrashed the Red Sox, 10-3.

After a season dominated by road blocks thrown in their path, the Yankees have found their footing. They have made key moves that have worked out nicely (see the shift of Joba Chamberlain into the starting rotation), they are getting excellent pitching from both veterans and youngsters and their offense is peaking.

They have won eight in a row since the All-Star break, their best start post-break since 1947. After being as many as nine games out of a playoff spot, they are now only one game behind the Red Sox. The Yankees are in the best position they’ve been in all season.

“We ran into a tough stretch in the first half with a lot of injuries,” said leadoff man Johnny Damon. “Right now, we’re playing well. We just need to keep that confidence going. … We’re feeling pretty good about our team.’

“The All-Star break came at the right time for us,” Damon said.

What makes the feeling even better is that reinforcements who brighten the Yankees’ picture even more, arrived yesterday.

Xavier Nady, a proven, veteran outfielder who was hitting .330 with 13 home runs for Pittsburgh, arrived shortly before game time and was inserted into the seventh spot in the order. He fills a huge hole the Yankees had in left field with Hideki Matsui out with an injured left knee and Damon slowed by a left shoulder strain.

“He’s right-handed (an area where the Yankees needed help) and a productive hitter,” manager Joe Girardi said of Nady. “He’s driving in runs and doing everything you’d want a hitter to do.”’

Nady was obtained along with reliever Damaso Marte, a lefty who was sought by a number of teams.

Marte paid immediate dividends. He came on in the seventh inning yesterday with two runners on and the score 7-3, and struck out David Ortiz.

“He was outstanding,” Girardi said of Marte’s one-batter appearance. “He had a plan. He was going right at him. He had good life on his fastball, a good slider. It was a big out.”

He not only gives the Yankees a lefty in the bullpen — something the team did not have — he gives them a veteran lefty who can do more than situational work when the need arises.

The hot streak, combined with the new arrivals, has New York in great spirits.

“It’s a very good move for us,” Girardi said. “We’re happy to have them.”

Cashman, the guy who made the trade, was equally happy. In his case, he was looking at the long term as much as the short term. While his team gave up four players it felt have a chance to make it, led by reliever Ross Ohlendorf and 19-year-old outfielder Jose Tabata, this was not a case of mortgaging the future. Cashman noted that both Nady and Marte are signed through next season.

“To give up those pieces, I wouldn’t have done it if it was a rental for a few months,” Cashman said. “Having that flexibility to control those assets through 2009 means a lot.”

As he was driving to Boston on Friday, the talks became serious. He said he was in the visitors dugout at Fenway, as the Yankees were taking batting practice Friday night, when he and Neal Huntington, the Pirates’ general manager agreed to the basics of the trade.

Initially, two of the four prospects the Yankees dealt were incorrectly reported. Besides Ohlendorf and Tabata, the Pirates also get pitchers Jeff Karstens and Dan McCutchen. The trade was completed at 11 a.m. yesterday, enough time to get Marte and Nady to Fenway for their initiation in the Sox-Yankees rivalry.

There was a time when it appeared the two teams would not be battling for very much this year.

But that has changed. The Yankees are back and ready to carry on, as usual.

pkenyon@projo.com